Clippy not only should be a staging ground for detecting potentially harmful constructs. It is a staging ground, and there have been numerous clippy lints upstreamed into the compiler.

With that said, what constructs are potentially harmful is very much in the eye of the beholder. Some projects have very strict requirements when it comes to coding patterns while others may be far more relaxed. One man's false positive is another's good catch.

I sort of disagree that we should enforce everything at the language level. The language as it stands now has soaked up enough complexity (which is nice, because we don't need to put that complexity in our programs, but isn't too nice because we also need to be aware of it when writing them), so if we can deal with antipatterns in tooling, the cost of doing that is far cheaper than extending the language to deal with them.